This invention relates to the shaping of a sheet of calendered steel wire ply material into a tubular ply member and transferring the tubular ply member over a mandrel to an anvil, cutting the tubular member with a rotating knife to a required width for a tire ply and transferring the cut length to a tire building drum. Stretching of the ply during application to the drum is avoided and an exact wire count in the ply is provided. Also the desired width of the ply sheet material may be provided by splicing two calendered sheets with the sum of their widths equal to the circumference of the ply material.
Providing a wire reinforced tube which is cut to length for application to a tire building drum is shown in U.S. Pat. No. 4,987,808. An extruder is required to form the tubular member by extruding rubber through conduits in a coextrusion head. This is a continuous process and cannot be used with calendered wire reinforced flat sheets. Two tube gripper assemblies are required to support the extruded tube sections as they are transferred and cut to length.
The present invention is directed to guiding flat wire reinforced calendered sheet material through shaping rollers where it is shaped into a tube with opposite edges in abutting relation. The edges are spliced to form the tube which is cut to length and transferred to a tire building drum. Different width sheets may be spliced to form a sheet having a width greater than either of the spliced sheets so that a tube of the desired diameter may be obtained.
In accordance with one aspect of the invention there is provided a method of forming a tube of reinforced elastomeric material characterized by shaping a flat sheet of reinforced elastomeric material having a width equal to the circumference of the tube into a tubular shape splicing abutting edges of the sheet and cutting the tube into a predetermined band length for application to a tire building drum.
In accordance with another aspect of the invention there is provided a method of building a tire comprising applying an inner liner to an expandable tire building drum characterized by:
a. shaping a tube from a flat sheet of wire reinforced elastomeric material having a width equal to the circumference of the tube,
b. splicing the edges of the flat sheet with the reinforcing wires in the edges being in abutting relation,
c. cutting the tube into a tubular member of a predetermined band length,
d. transferring the tubular member to a position over the inner liner, and
e. applying other tire components over the tubular member.
In accordance with still another aspect of the invention there is provided apparatus for forming a tubular band of reinforced elastomeric material having a predetermined length and diameter from a flat sheet of reinforced elastomeric material, characterized by:
a. a tube former for shaping a flat sheet into a tubular member having a circumference equal to the width of the flat sheet,
b. a splicer for splicing abutting edges of the sheet at a splicing position, located downstream of the tube former,
c. a cutting apparatus for cutting the tubular member to a predetermined length, located at a cutting position downstream from the splicer;
d. a cylindrical mandrel supporting the tubular member at a position downstream from the splicer as it is being transferred to the cutting apparatus,
e. an anvil mounted on said mandrel at said cutting position, and
f. a transfer mechanism for gripping the tubular member and moving the tubular member axially of the mandrel.